p27^Kip1‐mediated controlled proliferation technology increases constitutive sICAM production in CHO‐DUKX adapted for growth in suspension and serum‐free media

Abstract

We have engineered dihydrofolate reductase-deficient (dhfr(-)) Chinese hamster ovary (CHO)-DUKX B11 cells adapted for growth in serum-free suspension cultures for unlinked muristerone-inducible expression of the cyclin-dependent kinase inhibitor p27Kip1 and constitutive expression of the soluble intercellular adhesion molecule-1 (sICAM), a potent common cold therapeutic. Conditional overexpression of p27Kip1 resulted in a sustained G1-specific growth arrest of transgenic CHO-DUKX associated with up to fivefold-increased specific sICAM productivity. Herein we exemplify the implementation of controlled proliferation technology in a major biopharmaceutical production cell line that is compatible with key requirements for large-scale production procedures, including constitutive transgene expression and anchorage-independent growth in serum-free media.